The present invention relates generally to a wrapper for a smoking article to create a reduced ignition propensity (IP) smoking article and, more particularly, to a smoking article having the ability to freeburn in a static state and reduced IP. Under some circumstances cigarettes may ignite fire-prone substrates if the article is laid or accidentally contacts the substrate. Therefore, a cigarette prepared from a wrapper, which diminishes the ability of the article to ignite a substrate, may have the desirable effect of reducing cigarette-initiated fires. Furthermore, a wrapper that concurrently confers on the cigarette the ability to freeburn in a static state and reduced IP character allows a beneficial reduction in the tendency of the article to ignite fire-prone substrates while maintaining consumer acceptability.
There have been various attempts to create a cigarette that has reduced IP and consumer acceptable attributes particularly taste and the ability to freeburn in the static state. Technologies that appear to provide such cigarettes are described in the patent literature. Cigarettes claiming to possess reduced IP are commercially available.
A factor that manufacturers consider in preparing a smoking article having reduced IP is whether currently used processes and equipment will remain substantially unchanged. One method for preparing a reduced IP paper involves the addition of elaborate equipment on a conventional papermaking machine. Cellulose fibers or particles suspended in water are sprayed from angular moving nozzles moving at an angle to a continuous forming moist web. This approach involves the coordinated angular movement of the spray nozzle and the about 400 feet per minute moving web to create spaced apart bands transverse to the web. The above-mentioned technology suffers from a number of deficiencies that limit consumer acceptability, IP reduction, and ease of manufacture. The technology requires expensive add-on equipment including a spray nozzle system and an associated slurry distribution system, pressure regulating system, and a means for carefully synchronizing the angular material distribution system with the underlying papermaking machine.
The reduced consumer acceptable properties of the prepared cigarettes are due to factors including reduced ability of the cigarette to freeburn in the static state, poor ash appearance, and variable taste profile.
The poor IP reduction performance achieved by cigarettes prepared with wrappers made using this technology is believed to be caused by a number of factors including difficulty in depositing an even layer of the cellulose fibers or particles, low efficiency of the cellulose fibers or particles to reduce the permeability of the underlying web, and poor reproducibility caused by fanning out of the sprayed material. Deficiencies in the approach that limit ease of manufacture include the difficulty in synchronizing the angular moving cellulose fibers and particles distribution apparatus with the underlying web forming apparatus and difficulty in reducing the banded moist web to dryness without disrupting the structure of the web.
Another technology involves adding discrete material regions to the dry web using organic solvent-based printing equipment. Organic solvents and non-aqueous soluble solutes are used to make the discrete regions on the web. The presence of organic solvents requires hoods to capture the solvent vapors and the corresponding further expenses.
In regard to commercially available cigarettes claiming to possess reduced IP, consumers may find their organoleptic experience wanting. Some technologies that are based on discretely treated areas for reduced IP cigarettes create a varying organoleptic experience as the consumption of the smoking article moves from treated area to non-treated areas.
One commercial product claiming to possess reduced IP is characterized by a tendency to extinguish when left burning in the static state—that is reduced freeburn. The article displays a less desirable taste when relit after being extinguished. Thus, although the cigarette may possess the reduced IP, the reduced freeburn property decreases consumer acceptability of the article.
Other factors affecting consumer acceptability are product appearance, including pleasing and consistent wrapper and ash character. Moreover, it is important that the construction of the smoking article exhibit a reasonable shelf-life while maintaining reduced IP.
Thus, there remains a need for a new and improved wrapper and smoking article having reduced IP while at the same time possessing a sufficient free burn. Also, there remains a need for a new and improved method for making a wrapper that can be used to create a smoking article having reduced IP and sufficient freeburn.